In a conventional gas turbine engine, such as a bypass turbofan engine, bypass or bleed air is extracted between stages of a multi-stage axial compressor for various purposes. For example, in a bypass engine, compressed air is extracted as bypass airflow which bypasses the core engine as is conventionally known. In an engine operated so that pressure in the bypass duct is relatively equal to pressure inside the compressor where the compressed air is being extracted, the relative mass flow of the air extracted increases as the compressor speed is reduced unless means for modulating the extraction airflow are utilized. In some engine applications, this increase in extraction airflow at lower speeds is undesirable, and, therefore, a conventional mechanical valve is typically utilized. The valve is positionable for throttling the extraction airflow so that as compressor speed decreases, the valve may be closed for preventing a corresponding increase in extraction airflow. The mechanical valve arrangement necessarily adds weight, complexity, and cost to the compressor system and requires a control system for varying the valve settings.